Buying a new air system is a major investment, and it can seem daunting at times: comprehensive compressed air audits, baselining systems, compressor controls, system controls, pipe sizing, variable speed technology, flow controllers, and list the list goes on. But how do you make the right choices from the start?
Get The Facts
With a completed compressed air system audit in hand, managers from Land-O-Frost, a meat packing plant in Searcy, Ark., arrived at a compressed air seminar hosted by Kaeser Compressors Inc. Not confident in the “one-size-fits-all” solution proposed by the auditing company, they were hoping to gain a better understanding of what they needed in a compressed air system and get help in their decision making process. The seminar covered compressor fundamentals, and the basics of system design and control. Almost immediately, Land-O-Frost could see a solution forming.
Land-O-Frost had several challenges to meet. The facility had several rotary screw compressors in various sizes and from different manufacturers totaling around 400 hp. The system was scattered all over the plant with no centralization, and there were space concerns about adding a new system.
Compounding the problem, there was no control system in place to coordinate the operation of individual units. Each ran independent on straight modulation control. When a compressor cut on, it ran non-stop at full load even if only a portion of its capacity was needed.
Make A Plan
Land-O-Frost had a clear goal: improve the air system’s reliability and compressed air quality while reducing energy consumption. Based on Land-O-Frost's usage patterns and demand profile, Kaeser recommended one 100 hp base load machine and a Kaeser variable speed drive unit as a trim compressor. Ample storage would help improve system performance and help reduce compressor cycling, so Land-O-Frost’s system includes one 3750 gallon tank and two 1550 gallon tanks.
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Air treatment system features Kaeser refrigerated dryer, |
Kaeser’s Sigma Air Manager (SAM) with Sigma Air Control plus, five gig hard drive, and modem would provide comprehensive control, remote monitoring and management services for all of the air system equipment. Land-O-Frost choose the optional Sigma Air Control plus software because it stores the operational data for future reporting, system audits, control optimization and long-term trending, as well as air demand tracking.
As a food manufacturing plant, Land-O-Frost needed completely clean, dry compressed air. Kaeser designed an air treatment system that included a dual- control refrigerated dryer, two oil-mist eliminators, and high-efficiency filtration.
Eight automatic drains are located throughout the system to remove condensate from the receiver tanks and other clean air treatment equipment. The compressed air condensate drains into the Aquamat condensate management system where the contaminants are separated from the water, reducing the amount of material that requires special disposal and allowing the contaminant-free water to be discharged into the municipal water system.
The system layout was developed in advance using Kaeser’s state-of-the-art Microstation drawings. In addition to two-dimensional installation drawings, system engineers created a four-color, 3-D “fly through” allowing executives from Land-O-Frost to experience what it would be like to walk through their new compressed air system installation. Based on Kaeser recommendations, the old location near the ammonia compressors was abandoned and another room near the receiving dock was chosen for the new centralized system.
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Kaeser's Sigma Air Manager (SAM) controls and monitors the |
Apply What You’ve Learned
With the Kaeser-provided drawings, Land-O-Frost handled the installation, and in a short time Kaeser personnel were on site for the official start-up. SAM was programmed to provide the most efficient control scenarios for the compressors - including the 100 hp back-up compressor from another manufacturer - and to monitor the performance of the clean air treatment equipment. After some adjustment to the flow control valve, the new air station was ready to go.
And the results speak for themselves. With the new system up and running, the plant was using only about 175 hp – and that resulted in a 50 percent reduction in power consumption.Land-O-Frost is also able to continue improving the demand side of the air system with historical data provided by the SAM. In fact, this data helped properly size a blower package needed to operate a wastewater pit. Estimates indicate that Land-O-Frost can save another 15% in power cost savings by installing the new blower.
Executives at Land-O-Frost are justly proud of their installation, and the reliability factor is a big plus with the maintenance department. Brandon Barnett, maintenance supervisor, is impressed with the new system though he’s no longer a frequent visitor to the compressor room.
"Our old system was worked on every day, but this new one just takes care of itself. It's been almost three months since I last came into the compressor room," said Barnett. In fact, Barnett estimates that his labor crew spent 60-70 percent of their time on the old air system. Now, the total time spent is less than 4 percent.
As Land-O-Frost continued to monitor the data from SAM, they found that several key adjustments could be made in terms of compressor controls and equipment operation. A recent reading on their current horsepower consumption is down to 130 hp - 140 hp.
With a planned expansion in Madisonville, Ky., and another installation planned in late 2006, Land-O-Frost has opted to duplicate this air system in the new facilities to optimize their operations. However, given the most recent data provided by SAM, a slightly smaller system will be installed. Clearly another bonus for Land-O-Frost.
Not only are they saving thousands of dollars in power costs with improved reliability, they are also saving on capital expenditures and installation costs in their new facilities - right from the start.